Structural highlights
Function
[HA11_MOUSE] Involved in the presentation of foreign antigens to the immune system. [SPIKE_CVMJC] S1 attaches the virion to the cell membrane by interacting with murine CEACAM1, initiating the infection (By similarity). S2 is a class I viral fusion protein. Under the current model, the protein has at least 3 conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During viral and target cell membrane fusion, the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and plasma cell membranes (By similarity). [B2MG_MOUSE] Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Cytotoxic T lymphocyte escape occurs in many human infections, as well as mice infected with the JHM strain of mouse hepatitis virus, which exhibit CTL escape variants with mutations in a single epitope from the spike glycoprotein (S510). In all CTL epitopes prone to escape, only a subset of all potential variants is generally detected, even though many of the changes that are not selected would result in evasion of the T cell response. It is postulated that these unselected mutations significantly impair virus fitness. To define more precisely the basis for this preferential selection, we combine x-ray crystallographic studies of the MHC class I (D(b))/S510 complexes with viral reverse genetics to identify a prominent TCR contact residue (tryptophan at position 4) prone to escape mutations. The data show that a mutation that is commonly detected in chronically infected mice (tryptophan to arginine) potently disrupts the topology of the complex, explaining its selection. However, other mutations at this residue, which also abrogate the CTL response, are never selected in vivo even though they do not compromise virus fitness in acutely infected animals or induce a significant de novo CTL response. Thus, while structural analyses of the S510/D(b) complex provide a strong basis for why some CTL escape variants are selected, our results also show that factors other than effects on virus fitness limit the diversification of CD8 T cell epitopes.
Structural and biological basis of CTL escape in coronavirus-infected mice.,Butler NS, Theodossis A, Webb AI, Dunstone MA, Nastovska R, Ramarathinam SH, Rossjohn J, Purcell AW, Perlman S J Immunol. 2008 Mar 15;180(6):3926-37. PMID:18322201[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Butler NS, Theodossis A, Webb AI, Dunstone MA, Nastovska R, Ramarathinam SH, Rossjohn J, Purcell AW, Perlman S. Structural and biological basis of CTL escape in coronavirus-infected mice. J Immunol. 2008 Mar 15;180(6):3926-37. PMID:18322201
